Torque motor booster for clamp treadle of paper cutters



C. THUMIM May 26, 1959 2,887,895 MOTOR BOOSTER FOR CLAMP TREADLE OFPAPER CUTTERS Filed March 26, 1956 TORQUE 5 Sheets-Sheet l o 000 o o .MM: NU T mm r m g m C- THUMIM May 26, 1959 TORQUE MOTOR BOOSTER FOR CLAMPTREADLE OF PAPER CUTTERS Filed March 26, 1956 3 Sheets-Sheet 2 INVENTOR.

C. THUMIM TORQUE MOTOR BOOSTER FOR CLAMP TREADLE OF PAPER CUTTERS FiledMarch 26, 1956 3 Sheets-Sheet :5

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United States Patent TORQUE MOTOR BOOSTER FOR CLAMP TREADLE OF PAPERCUTTERS Carl Thumim, Westbury, N .Y., assignor to E. P. Lawson Co.,Inc., New York, N.Y., a corporation of New York Application March 26,1956, Serial No. 573,942 Claims. (Cl. 74-388) This invention relates toguillotine type paper cutters and more particularly to the clampactuating means thereof.

The purpose of this invention is to provide means for augmenting themanual effort required for pressing a clamp-operating foot pedal of apaper cutter. Thus, in paper cutters having manually operable cutters,wherein an operator has to step on the treadle to actuate the clamp,considerable force is needed. Such force may vary from 40 pounds at thebeginning of a stroke to about 140 pounds at the end of a stroke.Needless to say, repetitious effort of this kind becomes exceedinglytiring. Accordingly, the invention provides power operated means foreffecting most of the required force. The effort exerted by the operatoris in an amount to supply the difference between the actual clampingforce required and the force effected by the force boosting devicedisclosed herein. Such ditference in force which must be provided by theoperator can be held to a minimum limit so as to normally preclude atiring effect.

The invention can be used in conjunction with automatic clamp actuatingmechanisms for purposes of manually gauging a out, since disturbance ofthe paper pile by the relatively slow action of my manual arrangementwith power booster is kept to a minimum.

Briefly, the invention comprises the use of an electric motor of a typewhich can remain non-rotative even while current is going therethrough,without burn-out, the motor shaft, however, exerting a torque which maybe mechanically coupled to the clamp through the same linkage as isactuated by the foot treadle. Such motor torque thus augments the foottreadle force and may, of course, be considerably in excess thereof. Thearrangement is such that the motor is automatically energized when thefoot treadle is initially pressed.

Other objects and features will be apparent from the detaileddescription of the invention which now follows in conjunction with theappended drawing in which:

Figure 1 is a front View of a guillotine type paper cut ter showing thegeneral arrangement of certain elements which make up the novelcombination.

Figure 2 is an amplified view of a portion of Figure 1 showing detailsof the elements.

Figure 3 is an amplified drawing of the motor switch actuating device.

Figure 4 is a fragmentary elevation showing the arrangement of the motorand certain elements driven thereby.

Figure 5 is a forward view showing the motor driving arrangement.

Figure 6 is a fragmentary drawing of certain details of the combination.

Referring now to the drawing, the invention comprises a paper cutter, asshown, having the usual frame F carrying the knife K behind which isclamp C. The details of the clamp are not shown since it is conventionalin character and operated by a conventional arrangement, for

example, as shown generally in Patent No. 2,570,873 owned by theassignee of the present invention. Such arrangement comprises a spring Sand other elements heretofore well known. Thus, the spring S biasestreadle T through sprocket chain 6 to a position where the clamp is notin use. A dog D is fastened to a rod R which rides in a suitable bearingin the machine framing. The dog D abuts a pin P and transmits forcethereto to motivate the clamp in a manner as set forth in theabovementioned patent.

Sprocket chain 6 has one end secured to the dog D and thence passesaround an idler sprocket 9. The other end of the chain is secured to thefoot treadle T through a yoke 4 having spaced arms 4a and 4b throughwhich a pin 7 passes and which yoke carries a switch to be actuated in amanner to be described.

As shown in Figures 1 and 4, an arm 8 is integral with the foot threadlewhich may be pivoted at 12 to the machine frame. Any suitable mode offastening the pin 7 with the arm 8 may be used, the details of which arenot essential. The chain 6 terminates in a pin 40 which passes throughthe top portion 40 of the yoke and has bearing in a spring housing 42welded to portion 40. Within the spring housing a spring 43 is disposedbearing against a nut 45 threaded on pin 40. The weight of the treadleis thus carried on the spring 43. A small gap 45a exists between the nut45 and the bottom of the spring housing 42. Thus, it will be apparentthat owing to the integral fastening of the yoke with the spring housing42, if force be applied to the treadle the spring 43 will be compressedbecause the yoke 4 is initially pulled down, nut 45 being momentarilystationary due to the resistance chain 6 meets via dog D and pin P. Thebottom surface of the housing 42 meets the nut 45 to limit the relativemotion.

A switch 46 is carried within the yoke 4 having a pin 46a which isreleased when the yoke moves downwardly to a sufiicient extent to closethe lost motion gap between elements 42 and 45. Release of pin 46aserves to close the switch to energize an electric motor 50 carried bythe machine frame.

The shaft 50a (Figure 4) of the motor carries a sprocket wheel 54 whichis connected by a sprocket chain 56 to a sprocket wheel 57 which drivesa shaft 58 carrying a sprocket 60. The sprocket 60 has the end of asingle length of chain 64 (Figure 2) fastened thereto at 61, the otherend being fastened to an arm 66 which is secured to the sprocket 9 as bybolts 68.

From the above description it will be apparent that if the motor turnsclockwise, the chain 64 will efiect a downward pull on arm 66 to exertforce on the sprocket chain 6. This causes I e pin P to move to theright for the purpose of lowering the clamp through mechanism describedin Patent No. 2,570,873.

When the treadle is released, the spring S pulls the combinationcomprising chain 6 and yoke 4, etc. back to starting position, at whichtime the gap between spring housing 42 and nut 45 is once more created,the lower end of pin 40 then serving to push the pin 46a back to opencontact position.

A particular feature of the arrangement is that the torque effect of thelever 66 is gradually increased due to the change in moment arm inlength from d to D as shown in Figure 2. Thus, as the stroke of theclamp progresses the force on the clamp due to the motor is constantlyincreasing. This has the advantage of balancing the force needed toovercome the increasing load of the clamp return springs as used in aconventional clamp mechanism.

The particular arrangement is so designed that the motor will supplysomewhat less force than is required assaees for full movement of theclamp, the additional force being provided by the operator acting on thetreadle. Owing to the fact that the particular type of motor used willnot overheat even though energized without rotating for a period ofperhaps two minutes, the operator can keep his foot on the treadle forthat period at least, being materially assisted by the torque of themotor in maintaining the clamp pressure on the paper pile. While themotor can be designed for continuous energization, it would require alarger motor costing a great deal more.

' From the above it will be apparent that an operator need supply only asmall part of the energy required for clamping the paper pile while atthe same time having full and immediate control of the clamping action.

I'am aware that various modifications of the basic concept are possibleand accordingly do not seek to be limited to the exact arrangementdisclosed hereinabove except as set forth in the appended claims.

I claim:

1. In a clamp mechanism for a paper cutting machine, a manually operabletreadle, a sprocket wheel, a sprocket chain passing over a portion ofsaid wheel and having one end connected to a clamp actuating device andthe other end connected to said treadle; an electric motor, and tensilemeans connecting said motor to said sprocket wheel so as to efiect abooster torque on said wheel when said motor is energized.

2. In a device as set forth in claim 1, including a torque arm on saidsprocket wheel, said tensile means being connected to said torque arm,said torque arm being disposed to efiect increasing torque on saidsprocket wheel during the course of rotation.

3. In a clamp mechanism for a paper cutting machine, a manually operabletreadle, a sprocket wheel, a sprocket chain passing over a portion ofsaid wheel having one end adapted for connection to a clamp actuatingdevice and the other end connected to said treadle, a switch controlmeans, an electric motor, means connecting said motor for exerting abooster pull on said sprocket chain, said sprocket chain being connectedto said treadle through i 4 said switch control means, whereby initialmanual pressure on said treadle closes said switch to energize saidmotor.

4. In a device as set forth in claim 3, said switch control meanscomprising a housing, a switch carried in said housing, said housingbeing secured to said treadle, a spring in said housing, said sprocketchain having an element abutting an end of said spring, the other end ofsaid spring abutting a portion of said housing whereby said spring is ininitial compression by virtue of the weight of said treadle, saidhousing having a lost motion connection with said abutting element, aswitch carried by said housing actuated by take-up of lost 'rnotion whensaid housing is initially motivated by manual pressure on said treadle.

5. In a clamp mechanism for a paper cutting machine, a manually operabletreadle, actuating means mechanically connected to said treadle formoving a clamp by direct action of said treadle when an operator appliesforce thereto, and means for augmenting the force applied by saidoperator on said manually operable treadle comprising an electric motormechanically coupled to said actuating means, and means for energizingsaid motor when said manually operable treadle is initially actuated,said actuating means comprising a sprocket wheel, a sprocket chainaround a portion of said wheel having an end extending to said clampactuating means and another end connected to said treadle, an electricmotor mechanically coupled to said sprocket wheel, and means forenergizing said motor to exert torque on said sprocket wheel uponinitial motion of said treadle.

References Cited in the tile of this patent UNITED STATES PATENTS819,718 Bredenberg May 8, 190.6 1,191,612 Radiguer July 18, 19161,409,821 Bremberg Mar. 14, 1922 2,330,569 Esnault-Pelterie Sept. 28,1943 2,505,555 Levy Apr. 26, 1950

